System and Method for Aligning and Engaging a Topside to a Floating Substructure

1 . A system for engaging a topside with a substructure during float-over installation of the topside, the system comprising:

an alignment member coupled to the substructure;

an extendable member coupled to the topside, the extendable member having a receptacle configured to receive the alignment member; and

a damping system configured to move the extendable member into engagement with the substructure, wherein the alignment member is received within the receptacle.

2 . The system of claim 1 , wherein the damping system is further configured to:

apply force to the extendable member; and

resist force from the extendable member.

3 . The system of claim 2 , wherein the damping system is configured to resist force from the extendable member due to downward movement of the topside relative to the substructure.

4 . The system of claim 2 , wherein the damping system is configured to apply force to the extendable member when the topside moves upward relative to the substructure.

5 . The system of claim 2 , wherein the damping system is further configured to allow the extendable member to retract with relative vertical movement of the topside and the substructure are less than a predetermined amount.

6 . The system of claim 2 , wherein the extendable member remains engaged with the substructure under the force applied to the extendable member.

7 . A system for engaging a topside with a substructure during float-over installation of the topside, the system comprising:

an alignment member coupled to the substructure;

an extendable member coupled to the topside, the extendable member having a receptacle configured to receive the alignment member; and

a damping system comprising:

a piston-rod assembly comprising:

a piston slideably disposed with a housing, wherein a first chamber and a second chamber are formed; and

a rod coupled between the piston and the extendable member;

a source of pressurized gas coupled to the first chamber; and

an accumulator containing fluid coupled to the second chamber.

8 . The system of claim 7 , wherein the damping system is configured to resist force from the extendable member by injecting pressurized gas into the first chamber, wherein the pressurized gas reacts against the force of the extendable member.

9 . The system of claim 8 , wherein the damping system is further configured to allow the pressurized gas in the first chamber to compress under the force of the extendable member.

10 . The system of claim 9 , wherein the damping system is further configured to exhaust a portion of the pressurized gas from the first chamber when compressed.

11 . The system of claim 9 , wherein fluid is drawn into the second chamber as the pressurized gas is compressed.

12 . The system of claim 9 , wherein the extendable member is retractable as the pressurized gas is compressed.

13 . The system of claim 7 , wherein the damping system is configured to apply force to the extendable member by injecting pressurized gas into the first chamber, wherein the pressurized gas exerts force against the piston.

14 . The system of claim 13 , wherein the extendable member is extendable under the force applied by the pressurized gas against the piston.

15 . The system of claim 14 , wherein the damping system is further configured to exhaust fluid from the second chamber into the accumulator as the extendable member extends.

16 . The system of claim 14 , wherein the extendable member remains engaged with the substructure under the force applied by the pressurized gas against the piston.

17 . The system of claim 14 , wherein pressurized gas is drawn into the first chamber as the extendable member extends.

18 . A method for engaging a topside with a substructure during float-over installation of the topside, the method comprising:

extending a member having a receptacle from the topside to engage an alignment member coupled to the substructure;

applying force to the member to resist downward motion of the topside relative to the substructure; and

applying force to the member to maintain engagement of the member with the substructure in response to upward motion of the topside relative to the substructure.

19 . The method of claim 18 , further comprising retracting the member when the relative vertical movement between the topside and the substructure reaches a predetermined amount as the substructure is deballasted.

20 . The method of claim 18 , wherein the extending comprises injecting a pressurized gas into a first chamber, wherein the pressurized gas exerts force on a piston coupled to the extendable member, wherein the piston translates.

21 . The method of claim 20 , further comprising exhausting fluid from a second chamber as the piston translates.

22 . The method of claim 18 , wherein the applying force to the member to resist downward motion comprises injecting a pressurized gas into a chamber, wherein the pressurized gas exerts force against a piston coupled to the extendable member.

23 . The method of claim 18 , wherein the applying force to the member to maintain engagement comprises injecting a pressurized gas into a chamber, wherein the pressurized gas exerts force on a piston coupled to the extendable member, wherein the piston translates.

24 . The method of claim 23 , further comprising exhausting fluid from a second chamber as the piston translates.